CHARGE REPLACEMENT NEAR THE PHOSPHORYLATABLE SERINE OF THE MYOSIN REGULATORY LIGHT-CHAIN MIMICS ASPECTS OF PHOSPHORYLATION
CHARGE REPLACEMENT NEAR THE PHOSPHORYLATABLE SERINE OF THE MYOSIN REGULATORY LIGHT-CHAIN MIMICS ASPECTS OF PHOSPHORYLATION
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DOI：
10.1073/pnas.91.4.1490
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发表时间：
1994-02-15
影响因子：
11.1
通讯作者：
TRYBUS, KM
中科院分区：
文献类型：
--
作者：
SWEENEY, HL;YANG, ZH;TRYBUS, KM
肌球蛋白调节轻链（rlc）的磷酸化激活平滑肌收缩并调节横纹肌的力产生。RLC磷酸化改变了N端关键区域的净电荷，从而可能改变RLC与肌球蛋白重链之间的相互作用。人类平滑肌RLC中的一系列n端电荷突变已经被设计出来，当重组成扇贝横纹肌束或分离的平滑肌肌球蛋白时，这些突变体已经被评估为模拟RLC磷酸化形式的能力。改变从Arg-13到Ser-19区域的净电荷可增强扇贝横纹肌的力，并在不影响atp酶活性或平滑肌肌球蛋白运动的情况下维持平滑肌肌球蛋白处于展开的丝状状态。因此，横纹肌中RLC磷酸化的作用及其调节平滑肌中折叠到延伸构象转变的能力可能是由于轻链N端净电荷的简单减少。磷酸化调节平滑肌肌球蛋白atp酶活性和运动性的能力涉及一个更复杂的机制。
Phosphorylation of the myosin regulatory light chains (RLCs) activates contraction in smooth muscle and modulates force production in striated muscle. RLC phosphorylation changes the net charge in a critical region of the N terminus and thereby may alter interactions between the RLC and myosin heavy chain. A series of N-terminal charge mutations in the human smooth muscle RLC has been engineered, and the mutants have been evaluated for their ability to mimic the phosphorylated form of the RLC when reconstituted into scallop striated muscle bundles or into isolated smooth muscle myosin. Changing the net charge in the region from Arg-13 to Ser-19 potentiates force in scallop striated muscle and maintains smooth muscle myosin in an unfolded filamentous state without affecting ATPase activity or motility of smooth muscle myosin. Thus, the effect of RLC phosphorylation in striated muscle and its ability to regulate the folded-to-extended conformational transition in smooth muscle may be due to a simple reduction of net charge at the N terminus of the light chain. The ability of phosphorylation to regulate smooth muscle myosin's ATPase activity and motility involves a more complex mechanism.